Answer: No. Let's examine what community property does and does not do in the attribution arena.
Community property, as you indicate, is a creation of state law. California law, for example, says that property earned (i.e., not acquired through inheritance or gift) during marriage is community property absent an agreement to the contrary. Thus, regardless of how title to a community asset is held, each spouse is deemed to own 50% of the asset.
Attribution rules of federal law have nothing to do with this arrangement. It is purely a matter of state law determining who owns the property in the first place. Once state law has told us who owns the property, federal attribution rules can attribute that ownership to other parties.
By its very nature, the California community property rules only operate on property owned by the husband or wife. If neither has an actual ownership interest in an asset, there is nothing for California law to treat as a community asset.
The classic case in this arena is the controlled group case of Aero Industrial. Mom owned 66% of A and 100% of B. The remaining 34% of A was in the name of Mom's son-in-law. There's no attribution for controlled group purposes between son-in-law and Mom. However, it turned out that the 34% was community property. Accordingly, under state community property law, Mom's daughter (son-in-law's wife), was treated as actually owning 17% of A. Mom was deemed to own the 17% daughter owned, and the total of 83% (66% + 17%) was enough to create a controlled group. (These issues are discussed in more detail in Chapter 7 of my book, Who's the Employer?.)
Contrast that with the situation posed in the question at hand. Mr. Owner actually owns 100% of the company. His daughter is deemed to own 100% of the company under the attribution rules of IRC sections 318 and 267 for some federal tax purposes, including determining whether she is a highly compensated employee.
Does she actually own 100% of the company? No. Her ownership is a legal fiction created for certain specific purposes of federal tax law and not for others. (For example, assuming she is age 21 or older, she is not deemed to own any of the stock for purposes of the controlled group rules.) Accordingly, because she does not own any stock under state law, there is nothing for state law to treat as community property. Moreover, neither section 318 nor section 267 permits double family attribution, so her husband is not deemed to own the stock that she is deemed to own by attribution from her father.
So the bottom line, based on the information in the question, is that the son-in-law is not a 5% owner and is not treated as owning any part of the company for purposes of the traditional affiliated service group rules under 318, or the management function group rules under 267.
However, just to complete the picture, the prohibited transaction rules of IRC 4975 use a modified version of the attribution rules under IRC 267. Under IRC 4975, there is attribution directly from an owner to the spouses of the owner's lineal descendants. Accordingly, for purposes of the prohibited transaction rules, the son-in-law is deemed to own 100% of the company and thus is a disqualified person. This has nothing to do with community property rules -- it is rather an operation of the attribution rules under IRC 4975.
By the way, one of the more useful aspects of the new second edition of my book, Who's the Employer?, is a chart in the back that compares all the various attribution rules applicable to qualified plans.